Browsing by Subject "surface"
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(2011)Generation of raw materials for dry powder inhalers by different size reduction methods can be expected to influence physical and chemical properties of the powders. This can cause differences in particle size, size distribution, shape, crystalline properties, surface texture and energy. These physical properties of powders influence the behaviour of particles before and after inhalation. Materials with an amorphous surface have different surface energy compared to materials with crystalline surface. This can affect the adhesion and cohesion of particles. Changes in the surface nature of the drug particles results in a change in product performance. By stabilization of the raw materials the amorphous surfaces are converted into crystalline surfaces. The primary aim of the study was to investigate the influence of the surface properties of the inhalation particles on the quality of the product. The quality of the inhalation product is evaluated by measuring the fine particle dose (FPD). FDP is the total dose of particles with aerodynamic diameters smaller than 5,0 µm. The secondary aim of this study was to achieve the target level of the FPD and the stability of the FPD. This study was also used to evaluate the importance of the stabilization of the inhalation powders. The study included manufacturing and analysing drug substance 200 µg/dose inhalation powder batches using non-stabilized or stabilized raw materials. The inhaler formulation consisted of micronized drug substance, lactose <100µm and micronized lactose <10µm. The inhaler device was Easyhaler®. Stabilization of the raw materials was done in different relative humidity, temperature and time. Surface properties of the raw materials were studied by dynamic vapour sorption, scanning electron microscopy and three-point nitrogen adsorption technique. Particle size was studied by laser diffraction particle size analyzer. Aerodynamic particle size distribution from inhalers was measured by new generation impactor. Stabilization of all three raw materials was successful. A clear difference between nonstabilized and stabilized raw materials was achieved for drug substance and lactose <10µm. However for lactose <100µm the difference wasn't as clear as wanted. The surface of the non-stabilized drug substance was more irregular and the particles had more roughness on the surface compared to the stabilized drug substances particles surface. The surface of the stabilized drug particles was more regular and smoother than non-stabilized. Even though a good difference between stabilized and non-stabilized raw materials was achieved, a clear evidence of the effect of the surface properties of the inhalation particles on the quality of the product was not observed. Stabilization of the raw materials didn't lead to a higher FPD. Possible explanations for the unexpected result might be too rough conditions in the stabilization of the drug substance or smaller than wanted difference in the degree of stabilization of the main component of the product <100µm. Despite positive effects on the quality of the product were not seen there appears to be some evidence that stabilized drug substance results in smaller particle size of dry powder inhalers.
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(University of HelsinkiHelsingin yliopistoHelsingfors universitet, 2009)Salmonella and Campylobacter are one the most significant enteric bacterial organisms causing foodborne infections world-wide. Domestic Finnish broiler meat is rarely contaminated with Salmonella. Campylobacter contamination rate of domestic broiler meat is 10-30 % in summer months, during the seasonal peak of human campylobacter infections. The human campylobacter infections are usually sporadic and the source of infection remains unknown. Impact of domestic broiler meat on the incidence of these infections is unclear. In several case-control studies performed all over the world, consumption of poultry products and cross-contamination are recorded as risk factors for human Campylobacter infection. If broiler meat is contaminated by Campylobacter or Salmonella, the bacteria most probably contaminate kitchen surfaces in contact with the meat. The previous studies on contamination caused by broiler meat are mainly focused on quantitative transfer rates of the bacteria. In this thesis the kitchen contamination was studied using fluorescent liquid injected in broiler meat packages to document contact of meat or meat juice with the surfaces. The used method provides information on how widely and where the bacteria might spread in the kitchen. The study compared contamination on kitchen surfaces and utensils, caused by whole frozen broilers (25 units) and marinated broiler legs (25 units). The frozen broilers were prepared in a test kitchen, cut into pieces and spiced and cooked in oven pan. Marinated legs were opened from the packages and cooked in oven. After handling of each broiler meat unit, contamination on defined areas of kitchen surface and utensils were documented using ultraviolet light marked surface areas in the kitchen. Handling of marinated broiler legs decrease steps of meat handling in the kitchen. As expected, the cutting board and the spice cupboard remained clean with every marinated broiler leg unit. Correspondingly, those surfaces contaminated in the handling of whole frozen broiler unit. In handling of frozen broilers, meat-contact surfaces (i.e. counter and knife blade) contaminated significantly more often (p<0.001) compared to broiler legs. Dishcloths, commonly indicating the cleanness levels in the kitchen were contaminated also more (p<0,001) after handling of whole broiler units. Through hand-contact of whole broilers, the left trash cupboard with the door handle and the knife handle contaminated more often (p<0,001) than in the handling of marinated broiler legs. The right side trash cupboard contaminated more often (p=0,002) in handling of broiler legs than in the handling of whole broilers. The difference of contamination was not statistically significant between the handle of right-hand side trash cupboard and the water tap (trash bin door handle p=0,347, water tap p=0,101). Our study showed, that handling of whole frozen broiler carcasses cause significantly higher risk of cross-contamination appearing in the kitchen. Marinated broiler legs cause only little contamination on kitchen surfaces and utensils. However, cross-contamination is still possible through hands after handling of these products.
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